Sheet metal piles are normally interlocked to each other in side by side vertical relation to prevent adjoining piles from being separated. Adjoining side edges of sheet metal piles have interlocking male and female edges, such as tongue and groove joints, that are first vertically aligned and registered. Vertical alignment of the interlocking edges is accomplished by raising the undriven pile to a height above the previously driven pile and then moving the lower end of the undriven pile laterally until the adjacent edges are vertically aligned. Then, the interlocking portion of the undriven pile is threaded or stabbed within the subjacent interlocking portion of the driven interfitting pile by lowering of the undriven pile. In this position, the undriven pile is driven to the desired depth in the supporting surface while interlocked with the adjacent driven pile.
A problem exists in the vertical alignment or registering of the interfitting side edges for threading as the raised piles have to be moved laterally and a workman below the raised pile cannot manually contact and move the raised pile laterally for alignment. One method employed heretofore has been to position a workman on the upper ends of the driven piles for manually positioning the raised pile. However, such a method is unsafe particularly in the event of high wind conditions.
As shown in U.S. Pat. No. 4,189,256 dated Feb. 19, 1990, one method has been utilized heretofore to permit a vertical alignment of aligned interlocking side edges of adjacent piles without having a workman positioned on the upper ends of the driven piles. Such a method has utilized a mechanical guiding or threading device which is connected to an open side flange of the driven pile for vertical movement along the side flange while supporting the unsecured pile thereon. The mechanical guiding device has rollers engaging opposed surfaces of the driven pile and is attached to the driven pile by a workman on a lower supporting surface below the upper end of the driven pile. To move the unsecured pile laterally for alignment, spring urged plungers after attachment of the device to the driven pile are cocked and released prior to the upward vertical movement of the mechanical threading device and undriven pile along the driven pile. The spring urged plungers continuously urge a support on the threading device for the unsecured pile laterally. The mechanical threading device and the unsecured pile are lifted vertically by an overhead crane engaging the upper end of the unsecured pile and when the lower end of the unsecured pile clears the upper end of the adjacent driven pile, the unsecured pile is moved laterally automatically by the spring operated plungers to align the interfitting side edges vertically. Then, the unsecured pile and mechanical threading device are lowered with the interfitting side edges being threaded and remaining in interlocked position. Upon removal of the mechanical device, the unsecured pile is then driven by a pile driver to the predetermined depth in the supporting surface. Such a mechanical device is sold by the L. B. Foster Company, Pittsburgh, Pa. as a Dawson sheet pile threader.
However, in practice, it has been found that the automatic shifting or movement of the lower end of the raised pile laterally into vertical alignment with the driven pile does not always function properly and a workman oftentimes has to be positioned on the upper ends of the driven piles in order to obtain the accurate vertical alignment required for threading and registering of the interlocking side edges. Particularly after substantial use of the mechanical device, the plunger springs may lose part of their resilience and rust often occurs between moving parts of the mechanical device. Also, the size, length, and weight of various piles vary substantially and it is common to utilize only a single size of pile threader for the various types of piles.
U.S. Pat. No. 2,583,928 dated Jan. 29, 1952, shows a steel sheet pile threader in which the lower end of a raised pile is shifted laterally by pulling of a lanyard by a workman below the pile for effecting a camming of the lower end of the raised pile in a lateral position for vertical alignment with the driven pile. Rollers on the threader engage opposed sides of the driven pile for guiding the vertical movement of the pile being raised. The rollers are moved toward and away from the driven pile by the rotation of bolts connecting the rollers. The positioning or securement of the threader onto the driven pile for vertical movement along the driven pile and the subsequent positioning of the undriven pile in supporting relation on the threader is oftentimes time consuming as accurate positioning is required. Also, a safety hazard is presented to workman in the positioning and operation of the threader.